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The reaction of α,β-unsaturated aldehydes with tetra-allystannane (1, 0.25 equivalents) results in regioselective 1,2-addition to generate the corresponding allylic-vinylic alcohols in good to excellent yields (> 90%). Reactions with the equivalent ketones also proceed well (15-91%j although requiring more forcing conditions. Under these conditions, a second reaction pathway was evident for ketones that were less substituted at C3, namely that of methanolysis at C3. In all instances these reactions are elegant in their simplicity and show high levels of atom efficiency not typically found in similar methodologies for the synthesis of allylic-vinylic alcohols.

Opening of epoxides can be an effective means by which a variety of functional groups can be incorporated. In this letter, we outline how variation of conditions, in particular, that of solvent and concentration, give rise to different products using the Lewis acid catalyst BiCl3. (c) 2005 Elsevier Ltd. All rights reserved.

The reaction of 3-substituted indoles with 2-cyclohexenone under Lewis acid mediated conditions with Bi(NO3)3·5H2O has been investigated. We have demonstrated that electrophilic substitution of 3-substituted indoles with 2-cyclohexenone will readily occur at the nitrogen. Furthermore, the extent of regioselectivity is dependent on reaction solvent and the C3-substituent. Excellent conversion is obtained with good to excellent isolated yields of N- and C2-adducts. In general, more polar, aprotic solvents (CH3CN) give greater N-selectivity whereas with polar protic solvents (CH3OH) an increase in the C2-adduct is observed.

The reaction of α,β-unsaturated aldehydes with tetra-allystannane (1, 0.25 equivalents) results in regioselective 1,2-addition to generate the corresponding allylic-vinylic alcohols in good to excellent yields (> 90%). Reactions with the equivalent ketones also proceed well (15-91%j although requiring more forcing conditions. Under these conditions, a second reaction pathway was evident for ketones that were less substituted at C3, namely that of methanolysis at C3. In all instances these reactions are elegant in their simplicity and show high levels of atom efficiency not typically found in similar methodologies for the synthesis of allylic-vinylic alcohols.

The endogenous gibberellins in immature seeds of Prunus persica were analyzed by gas chromatography-mass spectrometry. Eleven known gibberellins, GA(3), GA(9), GA(17), GA(19), GA(30), GA(44), GA(61), GA(63), GA(87), GA(95) and GA(97) were identified. Additionally, several hitherto unknown gibberellins were detected and their putative structures were verified by synthesis of the authentic gibberellins. These gibberellins were then assigned trivial numbers, e.g. 1alpha-hydroxy GA(20) (GA(118)), 1alpha-hydroxy GA(9) (GA(119)), 1,2-didehydro GA(9) (GA(120)), 1,2-didehydro GA(70) (GA(121)), 1,2-didehydro GA(69) (GA(122)) and 1,2-didehydro GA(77) (GA(126)). GA(118) and GA(119) were the first 1alpha-hydroxy gibberellins identified from higher plants. The above profile of 1,2-didehydro gibberellins suggests that 1,2-dehydrogenation might occur prior to 3beta-hydroxylation in biosynthesis of GA(3), GA(30) and GA(87) in immature seeds of P. persica.

We report a simple procedure for the indium-mediated addition of 4-bromocrotonic acid to a variety of aldehydes and ketones. In all instances the reaction proceeds exclusively with α-addition and typically in moderate to good yields (42–100%). The effect of solvent is minimal allowing a wide choice of conditions (methanol, ethanol, ethanol/water, water, tetrahydrofuran, and the ionic liquid [bmIm][BF4]).